The present invention relates generally to lighting techniques. In particular, the present invention provides a method and device using a plasma lighting device having a arc tube configured for an electrode-less plasma lamp using an radio frequency source. Merely by way of example, such plasma lamps can be applied to applications such as stadiums, security, parking lots, military and defense, streets, large and small buildings, vehicle headlamps, aircraft landing, bridges, warehouses, ultraviolet (UV) water treatment, agriculture, architectural lighting, stage lighting, medical illumination, microscopes, projectors and displays, any combination of these, and the like.
From the early days, human beings have used a variety of techniques for lighting. Early humans relied on fire to light caves during hours of darkness. Fire often consumed wood for fuel. Wood fuel was soon replaced by candles, which were derived from oils and fats. Candles were then replaced, at least in part by lamps. Certain lamps were fueled by oil or other sources of energy. Gas lamps were popular and still remain important for outdoor activities such as camping. In the late 1800, Thomas Edison, who is the greatest inventor of all time, conceived the incandescent lamp, which uses a tungsten filament within a bulb, coupled to a pair of electrodes. Many conventional buildings and homes still use the incandescent lamp, commonly called the Edison bulb. Although highly successful, the Edison bulb consumed much energy and was generally inefficient.
Fluorescent lighting replaced incandescent lamps for certain applications. Fluorescent lamps generally consist of a tube containing a gaseous material, which is coupled to a pair of electrodes. The electrodes are coupled to an electronic ballast, which helps ignite the discharge from the fluorescent lighting. Conventional building structures often use fluorescent lighting, rather than the incandescent counterpart. Fluorescent lighting is much more efficient than incandescent lighting, but often has a higher initial cost.
Shuji Nakamura pioneered the efficient blue light emitting diode, which is a solid state lamp. The blue light emitting diode forms a basis for the white solid state light, which is often a blue light emitting diode within a bulb coated with a yellow phosphor material. Blue light excites the phosphor material to emit white lighting. The blue light emitting diode has revolutionized the lighting industry to replace traditional lighting for homes, buildings, and other structures.
Another form of lighting is commonly called the electrode-less lamp, which can be used to discharge light for high intensity applications. Frederick M. Espiau was one of the pioneers that developed an improved electrode-less lamp. Such electrode-less lamp relied upon a solid ceramic resonator structure, which was coupled to a fill enclosed in a bulb. The bulb was coupled to the resonator structure via rf feeds, which transferred power to the fill to cause it to discharge high intensity lighting. Although somewhat successful, the electrode-less lamp still had many limitations. As an example, electrode-less lamps have not been successfully deployed. Additionally, electrode-less lamps are generally difficult to disassemble and assembly leading to inefficient use of such lamps. These and other limitations may be described throughout the present specification and more particularly below.
From the above, it is seen that improved techniques for lighting are highly desired.